Buggy code:
public static final String CLEAN = "clean" ; public static final String PUBLIC = "public" ; public static final String PROTECTED = "protected" ; public static final String DEFAULT = "default" ; public static final String PRIVATE = "private" ; public static final String NEVER = "never" ; public static final String JAVA_SOURCE_CONTENT_TYPE = ( JavaCore . PLUGIN_ID ) + ".javaSource" ; public JavaCore ( ) { } public static void addElementChangedListener ( IElementChangedListener listener ) { } public static void addElementChangedListener ( IElementChangedListener listener , int eventMask ) { } public static void addJavaElementMarkerAttributes ( Map attributes , IJavaElement element ) { } private static void addNonJavaResources ( Object [ ] nonJavaResources , IContainer container , int rootPathSegmentCounts , ArrayList collector ) { } public static void addPreProcessingResourceChangedListener ( IResourceChangeListener listener ) { } public static void addPreProcessingResourceChangedListener ( IResourceChangeListener listener , int eventMask ) { } public void configureJavaElementMarker ( IMarker marker , IJavaElement element ) throws CoreException { } public static IJavaElement create ( String handleIdentifier ) { } public static IJavaElement create ( String handleIdentifier , WorkingCopyOwner owner ) { } public static IJavaElement create ( IFile file ) { } public static IJavaElement create ( IFolder folder ) { } public static IJavaProject create ( IProject project ) { } public static IJavaElement create ( IResource resource ) { } public static IJavaElement create ( IResource resource , IJavaProject project ) { } public static IJavaModel create ( IWorkspaceRoot root ) { } public static IClassFile createClassFileFrom ( IFile file ) { } public static ICompilationUnit createCompilationUnitFrom ( IFile file ) { } public static IPackageFragmentRoot createJarPackageFragmentRootFrom ( IFile file ) { } public static IClasspathContainer getClasspathContainer ( IPath containerPath , IJavaProject project ) throws JavaModelException { } public static ClasspathContainerInitializer getClasspathContainerInitializer ( String containerID ) { } private static ClasspathContainerInitializer computeClasspathContainerInitializer ( String containerID ) { } private static void verbose_failed_to_instanciate_container_initializer ( String containerID , IConfigurationElement configurationElement ) { } private static void verbose_found_container_initializer ( String containerID , IConfigurationElement configurationElement ) { } public static IPath getClasspathVariable ( final String variableName ) { } private static void verbose_no_variable_initializer_found ( String variableName ) { } private static void verbose_variable_value_after_initialization ( String variableName , IPath variablePath ) { } private static void verbose_triggering_variable_initialization ( String variableName , ClasspathVariableInitializer initializer ) { } private static void verbose_triggering_variable_initialization_invocation_trace ( ) { } public static String getClasspathVariableDeprecationMessage ( String variableName ) { } public static ClasspathVariableInitializer getClasspathVariableInitializer ( String variable ) { } private static void verbose_failed_to_instanciate_variable_initializer ( String variable , IConfigurationElement configElement ) { } private static void verbose_found_variable_initializer ( String variable , IConfigurationElement configElement ) { } public static String [ ] getClasspathVariableNames ( ) { } public static Hashtable getDefaultOptions ( ) { } public static String getEncoding ( ) { } public static IResource [ ] getGeneratedResources ( IRegion region , boolean includesNonJavaResources ) { } private static void getGeneratedResource ( ICompilationUnit unit , IContainer container , State state , int rootPathSegmentCounts , ArrayList collector ) { } public static JavaCore getJavaCore ( ) { } public static String [ ] getJavaLikeExtensions ( ) { } public static String getOption ( String optionName ) { } public static Hashtable getOptions ( ) { } public static Plugin getPlugin ( ) { } public static IClasspathEntry getResolvedClasspathEntry ( IClasspathEntry entry ) { } public static IPath getResolvedVariablePath ( IPath variablePath ) { } public static IWorkingCopy [ ] getSharedWorkingCopies ( IBufferFactory factory ) { } public static String [ ] getUserLibraryNames ( ) { <START_BUG> return UserLibraryManager . getUserLibraryNames ( ) ; <END_BUG> } public static ICompilationUnit [ ] getWorkingCopies ( WorkingCopyOwner owner ) { } public static void initializeAfterLoad ( IProgressMonitor monitor ) throws CoreException { } public static boolean isClasspathVariableReadOnly ( String variableName ) { } public static boolean isJavaLikeFileName ( String fileName ) { } public static boolean isReferencedBy ( IJavaElement element , IMarker marker ) throws CoreException { } public static boolean isReferencedBy ( IJavaElement element , IMarkerDelta markerDelta ) throws CoreException { } public static IAccessRule newAccessRule ( IPath filePattern , int kind ) { } public static IClasspathAttribute newClasspathAttribute ( String name , String value ) { } public static IClasspathEntry newContainerEntry ( IPath containerPath ) { } public static IClasspathEntry newContainerEntry ( IPath containerPath , boolean isExported ) { } public static IClasspathEntry newContainerEntry ( IPath containerPath , IAccessRule [ ] accessRules , IClasspathAttribute [ ] extraAttributes , boolean isExported ) { } public static ITypeHierarchy newTypeHierarchy ( IRegion region , WorkingCopyOwner owner , IProgressMonitor monitor ) throws JavaModelException { } public static IClasspathEntry newLibraryEntry ( IPath path , IPath sourceAttachmentPath , IPath sourceAttachmentRootPath ) { } public static IClasspathEntry newLibraryEntry ( IPath path , IPath sourceAttachmentPath , IPath sourceAttachmentRootPath , boolean isExported ) { } public static IClasspathEntry newLibraryEntry ( IPath path , IPath sourceAttachmentPath , IPath sourceAttachmentRootPath , IAccessRule [ ] accessRules , IClasspathAttribute [ ] extraAttributes , boolean isExported ) { } public static IClasspathEntry newProjectEntry ( IPath path ) { } public static IClasspathEntry newProjectEntry ( IPath path , boolean isExported ) { } public static IClasspathEntry newProjectEntry ( IPath path , IAccessRule [ ] accessRules , boolean combineAccessRules , IClasspathAttribute [ ] extraAttributes , boolean isExported ) { } public static IRegion newRegion ( ) { } public static IClasspathEntry newSourceEntry ( IPath path ) { } public static IClasspathEntry newSourceEntry ( IPath path , IPath [ ] exclusionPatterns ) { } public static IClasspathEntry newSourceEntry ( IPath path , IPath [ ] exclusionPatterns , IPath specificOutputLocation ) { } public static IClasspathEntry newSourceEntry ( IPath path , IPath [ ] inclusionPatterns , IPath [ ] exclusionPatterns , IPath specificOutputLocation ) { } public static IClasspathEntry newSourceEntry ( IPath path , IPath [ ] inclusionPatterns , IPath [ ] exclusionPatterns , IPath specificOutputLocation , IClasspathAttribute [ ] extraAttributes ) { } public static IClasspathEntry newVariableEntry ( IPath variablePath , IPath variableSourceAttachmentPath , IPath sourceAttachmentRootPath ) { }

Fix:
return JavaModelManager . getUserLibraryManager ( ) . getUserLibraryNames ( ) ;